改性生物柴油碳烟与NOx排放试验

摘要

针对生物柴油氧化安定性较差、NOx排放偏高的情况,添加抗氧化剂(BHA)对生物柴油进行燃料改性,分析了抗氧化剂对生物柴油氧化安定性的影响,讨论了改性前、后生物柴油粘度随温度的变化规律.测量了高压共轨柴油机燃烧改性生物柴油的排放污染物随转速、负荷的变化规律.探讨了抗氧化剂改善生物柴油碳烟、NOx排放的作用机理.研究结果表明:燃料改性后,生物柴油的氧化安定性大幅度提高,燃油粘度略有降低;发动机的碳烟、NOx排放均明显下降,特别是在中、高负荷时效果显著;燃烧过程中抗氧化剂抑制了脂肪酸长链分子的高温裂解,促进了自由基的淬熄效应,由此改变了碳烟与NOx排放之间此消彼长的关系.%Because of the poor oxidation stability and the high NOX emissions, biodiesel fuel was redesigned by adding anti-oxidants. The oxidation stability and viscosity of the biodiesel have been measured and analyzed. The engine experiment was conducted and it was fueled by biodiesel and BHA/biodiesel, NO., emission and smoke were measured. The mechanism of anti-oxidants to decrease the smoke, Nox emission was discussed. The results showed that BHA additive was a high effective antioxidant of biodiesel, the viscosity of biodiesel was decreased slightly; and the emission smoke and NO., was decreased significantly, especially at the high load condition. Anti-oxidants can restrain the high-temperature dissociation of long-chain fatty acid molecules during the combustion process, and it can promote the quenching effects of free radical. Also, it can change the " trade-off" tradition relationship between smoke and NO., emissions.